Why were blue whales hunted?

Whales of a few kinds had fat which could be cooked down into a fuel oil for lighting. Some types also had a lighter oil in the head cavity which was used as a lubricant for fine machinery, such as watches and clocks and again as lamp oil. This was called spermaceti. The bony filters that whales used to sieve food from ocean water was used for making small curved springs whcih went into womens corsets which compressed the waist. Very fashionable then.

This was mainly before it was possible to make reliable spring steel. Kerosene was invented in 1846 - 47 (Abraham Gesner) but was not recognised as a lighting fuel straight away and a good burner for it was not developed until 1854 in Vienna by Ditmar. It took until about 1860 or so to replace most of the whale oil lamps with kerosene ones. Even after that spermaceti was still recommended as a watch and clock lubricant for forty years or more.

Ambergis - a deposit in some whale intestines was used as a perfume fixative.

Moby Dick by Melville actually gives a lot of information.

Uses of baleen

Baleen plates were formerly used in buggy whips and parasol ribs, and to stiffen parts of women's stays and dresses, like corsets. Baleen was commonly used to crease paper; its flexibility keeps it from damaging the paper. Its function now has been replaced by plastic. It was also formerly believed that baleen plates could be obtained from whale fins.

http://en.wikipedia.org/wiki/Baleen

One of the major reasons for the whaling trade was the collection of whale blubber. This was rendered down into oil in giant cauldrons or later, in vats on factory ships.

Retrieved from "http://en.wikipedia.org/wiki/Blubber%22

blue whales are hunted for their bones and make it into perfume

Actually they create it for Perfumes and Blubber but it's legal to the Government, for me it's illegal to kill innocent animals because God never Kill us why we kill animals?

for their blubber (good oil for lanterns) and their bones (perfume)

for blubber/fat